When it comes to pheromone mixing, you must know that some pheromone products are oil-based and some are alcohol-based. For example Primal Instinct and Scent of Eros use oil, while The Edge and New Pheromone Additive use alcohol base. If you use an atomizer and even if you shake your atomizer there is a chance the products won't mix well. To be able to mix different pheromone products, you'll need a calibrated glass dropper. It's not expensive, and it is available at the nearest pharmacy. Some pheromone products are stored in a roll-on bottle, others sometimes even in an open mouth bottle, however, some products have an integrated dropper you can use.
The basic idea about pheromone mixes is that by adding products together, you can maximize their effectiveness. And, if you have a mix that simply does not work, don't put more stuff into it - it is unlikely that this will make it work. Most mixes are very simple - and made of two products only. Some popular mixes include Scent of Eros (contains androstenol) plus NPA (contains androstenone), or Androstenone Pheromone Concentrate (APC) plus New Pheromone Additive.
Find out more about androstenone pheromones and androsterone pheromones at HumanPheromone.org